Apparatus for closing cardboard boxes and similar packages by means of adhesive tape



sept- 1970 B. J. ACHTERBERG 3,530,025

APPARATUS FOR CLOSING CARDBOARD BOXES AND SIMILAR PACKAGES BY MEANS OF ADHESIVE TAPE Filed June 26. 1968 Patented Sept. 22, 1970 Int. Cl. B32]: 31/00; G05g 15/00 US. Cl. 156-358 15 Claims ABSTRACT OF THE DISCLOSURE An apparatus for closing and sealing cardboard boxes by the application of adhesive tape lengthwise on the joints between the top and bottom closure flaps of the boxes. The boxes are advanced between self-adjusting lateral guide rails and underneath vertically movable slides with upwardly inclined entry ends allowing an advancing box to raise these slides to the level of the box height. Thereupon a locking device is automatically actuated to lock the slides against further upward movement, thereby allowing an adhesive tape applicator carried by these slides to stick-on the adhesive tape with the required sealing pressure.

BACKGROUND OF THE INVENTION The invention is concerned with an apparatus for closing cardboard boxes and similar packages or cartons by the application of adhesive tape on the upper side and, if so desired, also on the lower side of the boxes. More in particular, the invention is concerned with such an apparatus for closing and sealing cardboard boxes having two closure flaps meeting at a longitudinal joint in the centre of the upper face (and, as the case may be, also of the lower face) of the box, in which the adhesive tape is stuck longitudinally over this joint. In this connection, the expression adhesive tape is meant to cover selfsticking tape as well as tape, such as gummed tape, which has to be wetted before it is applied.

In many cases it is desired that a box closing and sealing apparatus of the above mentioned kind be able to handle boxes or other packages of various sizes and shapes which are fed to the apparatus in any sequence. This means that the apparatus should preferably adjust itself automatically to the width and height of the various boxes fed thereto. To that effect, it has been suggested to provide such an apparatus with a conveyor means for moving each successive box along a conveyor track through the apparatus, with se1fadjusting lateral parallel guide rail means for guiding and aligning the boxes with respect to this conveyor track, and with an elongated pressure member mounted for vertical movement above this conveyor track and extending lengthwise of this track, which pressure member is adapted to adjust itself to the height of a supplied box and carries an adhesive tape applicator for sticking a length of adhesive tape on the box passing underneath thereof. According to a known apparatus of such design, the movable pressure member with tape applicator is carried by four suspension rods which are coupled to appropriate tension springs for partly compensating the weight of the pressure device and tape applicator whereby the pressure member normally occupies a predetermined lower rest position. On its entry side the elongated pressure member may have upwardly inclined extensions or guide means so as to allow a box, which is advanced by the conveyor means against these guide members, to gradually raise the pressure member to the height of the box against the action of the downwardly directed force of the partly compensated weight of the pressure member and applicator device. Adhesive tape applicator devices of conventional type generally have spring-mounted pressure means, such as pressure rollers, for pressing the tape against the surface on which the tape is to be applied. The above mentioned downwardly directed force exerted on the box by the movably mounted pressure member should, therefore, be greater than the sealing pressure exerted on the upper side of the box by the pressure rollers of the applicator device since otherwise a proper sticking-on of the adhesive tape is not ensured. This means that the downwardly directed force exerted by the pressure member on the box must be relatively great. Furthermore, in the prior art apparatus this force does not have a constant value but increases as the pressure member is raised by the box to a higher level since the counteracting upward force of the tension springs tends to decrease as the pressure member is further raised. In the use of this knownapparatus there is thus the risk that in the course of the vertical adjustment of the pressure member by the advancing box engaging with its upper front edge the upwardly inclined entry guide means of this pressure member, the box is tilted forwardly or is compressed at its upper forward end. In the case of boxes of a relatively light material and boxes having light, not tightly packed contents, the upper wall of the box and even the contents: of the box may thus be damaged by the downward pressure of the pressure member. On the other hand, if the pressure force of the pressure member is decreased to avoid such damage, there is the risk that the adhesive tape is applied on the box with unsuflicient pressure and that the box is not properly sealed.

In another known box closure apparatus of the present type this problem is avoided by mounting the adhesive tape applicator device in a movable frame member which may be vertically adjusted by means of a screw spindle arrangement operated by hand or through an electric motor. This embodiment has, however, the disadvantage that it is not self-adjusting which makes this known apparatus impractical for handling a random sequence of boxes of varying heights.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a box closing and sealing apparatus of the character described which adjusts itself automatically to the height of the boxes fed thereto and which provides sufiicient sealing pressure without any risk of damage to the boxes or their contents.

More particularly, it is an object of the invention to provide an apparatus of the character described in which the force, to be exerted by the boxes for raising the pressure member and tape applicator to the required height, can be much smaller than the pressure exerted by the tape applicator on the box upper wall during the sticking of the adhesive tape thereon.

In view of these objects, according to the invention the box closing and sealing apparatus of the above described character comprises a locking device for the above mentioned vertically movable pressure member carrying the adhesive tape applicator which locking device is adapted to lock said pressure member in any vertical position within its range of vertical displacement and is controlled in its operation by first and second control means, in which said first control means is responsive to the passage of a box along the conveyor track of the apparatus and actuates said locking device as soon as said'pressure member has been adjusted to the desired level for said box, and said second control means causes said locking device to release said pressure member when said box has passed said adhesive tape applicator.

With this arrangement, the movable pressure member may be so mounted that it can be raised from its lowermost rest position by a light upward pressure of an advancing box engaging the inclined entry guide means of this pressure member. There is thus no risk of the box being tilted forwardly or being damaged during this engagement. As soon as the pressure member has been raised by the box to the desired level, the pressure member is locked in this position on its actuation by the first control means which responds when the advancing box passes a predetermined point of the cou veyor track. During the following passage of the box underneath the pressure member, this member because of its locked position can provide the necessary reaction force for a proper operation of the adhesive tape applicator. The pressure member holds down the upper closure flaps of the box but cannot exert a downward compressive force which might damage the box or the articles packed there.

As above mentioned, the pressure member of the box closing apparatus of the invention may be provided at its entry side with upwardly inclined entry guide means. According to a preferred embodiment of the invention, said first control means may be so arranged lengthwise of the conveyor track that this control means actuates the locking device just before the advancing box, engaging the entry guide means, has raised the pressure member completely to the height of the box. In this way the pressure member may exert a predetermined pressure on the upper closure flaps of the box passing there below whereby these flaps are properly held in their closed position during the application of the adhesive tape thereto. By making said first control means adjustable lengthwise of the conveyor track it is possible to adapt this closing pressure of the locked pressure member to the type of the box concerned and to the nature of the contents thereof.

BRIEF DESCRIPTION OF THE DRAWING Further features and advantages of the invention will appear from the following description in conjunction with the accompanying drawing showing by way of example a preferred embodiment of the box closing and sealing apparatus according to the invention. In the drawing:

FIG. 1 is partly a plan view of the apparatus and partly a horizontal section on the line I-I of FIG. 2 as seen in the direction of the arrows;

FIG. 2 is a vertical section of the apparatus on the line 11-11 of FIG. 1; and

FIG. 3 is an end view of the apparatus as seen in the direction of the arrow III of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1, 2 and 3 of the drawing, the apparatus there shown has an elongated rectangular tablelike frame 1 supported on legs 36 at its four corners. The frame is provided at its upper side with two spaced pairs of parallel roller tracks 2 carried by longitudinal frame members 37 and together forming a conveyor track for supporting the boxes to be closed, such as the box 34, in their passage through the apparatus from left to right as seen in the FIGS. 1 and 2 of the drawing. Two endless conveyor chains 3 extend between the pairs of roller tracks 2 in parallel relationship therewith. The conveyor chains pass around chain wheels 4 mounted at both ends of the frames 1, the chain wheels at one frame end being coupled to a conveyor drive motor in a known manner (not shown). Drive members 5 project from the conveyor-chains 3 which drive members may engage a box, such as the box 34, placed on the left hand or entry side of the roller track to advance this box through the apparatus. As shown, each chain 3 has two projecting drive members 5 secured thereto but it will be understood that, depending on the length of the chain, a greater number of equally spaced drive members may be provided. The spacing between the pairs of roller tracks 2 is such that the conveyor track formed thereby has a sufficient width to accommodate the smallest boxes to be handled by the apparatus. If desired, the rollers 2 may be replaced by suitable ball bearings for supporting the boxes in such a way that the latter may also be easily moved transverse of the conveyor track. As will appear from the following description, such transverse displacement especially occurs at the entry side of the conveyor track.

In its passage through the apparatus, each box is aligned and guided by a pair of lower lateral guide rails 6 and a pair of upper lateral guide rails 7. These guide rails extend lengthwise of the conveyor track and have laterally diverging entry ends 6' and 7', respectively, forming a funnel-shaped inlet for the boxes. The two lower guide rails 6 are oppositely arranged at a small distance above the plane of the conveyor track at both sides of the latter and are each carried by a pair of parallel horizontal supporting rods 8. The rods 8 are at one end articulated to the guide rail concerned and are at their opposite ends mounted for pivotal movement on vertical axes 9, 9' carried by the frame 1. The two guide rails 6 are thus each movable in a lateral direction toward and away from each other in which, however, they always maintain their parallel relationship. The two guide rails 6 are coupled with one another through a coupling arrangement comprising two link members 38, one secured to each axis 9', and two further link members 39 articulated at their outer ends to the link members 38 and at their inner ends to a pair of meshing toothed wheels 40 mounted on the frame 1. A tension spring 41 extending between the inner ends of the link members 39 tends to pull these members toward each other and thereby, through the members 38 and 8, tends to move the lower guide rails 6 to the innermost rest position (FIG. 1). By this coupling arrangement of the guide rails 6, a lateral displacement of one guide rail causes an equal displacement in the opposite direction of the opposite guide rail so that the two guide rails always maintain their parallel and symmetrical lateral positions with respect to the centre line of the conveyor track. Each box introduced between the guide rails 6 is thus automatically shifted to a centre position on the conveyor track.

The upper lateral guide rails 7 are carried by a vertically movable pressure member, generally indicated by 11, and are each supported by a pair of articulated supporting rods (not visible in the drawing) in a similar arrangement as above described for the supporting rods 8 of the lower guide rails 6. The supporting rods of the upper guide rails 7 are thus pivotal on vertical axes 10 (FIG. 3) whereby these guide rails are moveable in a lateral direction while maintaining their parallel relationship. The upper guide rails 7 are, however, not coupled with each other by a coupling arrangement as above described for the guide rails 6. Springs (not shown) urge the upper guide rails 7 to an innermost rest position similar to the rest position of the lower guide rails 6. If desired the rest positions of the guide rails 6 and 7 may be determined by suitable stop means (not shown).

The pressure member 11 comprises two parallel horizontal longitudinally extending pressure rails or slides 12 having upwardly inclined entry ends 12 The slides 12 are connected by two spaced cross rods 13 in which the axes 10 for the upper lateral guide rails 7 are pivotally mounted and to which four upwardly extending supporting rods 14 are fixedly secured. These supporting rods are articulated at their upper ends to the lower ends of four angle-cranked levers 15 which have their upper ends connected in pairs by two longitudinally extending link members 16. Each two angle-cranked levers 15 situated side by side at the forward end and rearward end, respectively, of the pressure member 11 are pivotally mounted on a common cross shaft 17 supported by uprights 18 mounted on the frame 1. This suspension arrangement of the pressure member 11 allows a swinging movement thereof comprising a major vertical displacement accompanied by a small longitudinal displacement, in which the slides 12 always maintain their parallel horizontal position.

The shaft 17 at the discharge end of the apparatus carries a toothed pawl wheel segment 19 which is fixedly connected to the cranked levers on this shaft so as to move together therewith. As schematically shown in FIG. 2, this pawl wheel segment cooperates with a moveable pawl member 20 to form a locking device for looking the pressure member 11 against vertical movement. The pawl member 20 is attached to a toggle lever 21 which cooperates with the armature of an electromagnet 23 in such a way that when the electromagnet is excited the armature thereof moves the pawl 20 into engagement with the pawl wheel segment 19 against the action of a tension spring 22. Upon subsequent de-excita'tion of the electromagnet 23, the spring 22 pulls the pawl 20 out of engagement with the pawl wheel segment 19.

The locking device 20-23 is mounted inside a cover member 42 which, as schematically indicated, covers the upper part of the apparatus and which may be removably secured to the uprights 18.

A first microswitch 24 is adjustably mounted on the entry end 12' of one of the slides 12 adjacent the upward bend of this entry end 12. The microswitch 24 has a switch arm 24' projecting downwardly into the path of movement of an advancing box on its engagement with this entry end. A second microswitch 25 is adjustably mounted on a frame member 43 extending between the conveyor chains 3 at the entry side of the apparatus. The switch 25 has a switch arm 25' projecting into the path' of movement of a trip dog secured to one of the conveyor chains 3. For reasons of clarity the microswitch 25 has only been shown in FIG. 1. The conveyor chain has two such trip dogs 44 secured thereto each arranged at such a distance to the rear of one of the drive members 5 that one of the trip dogs actuates the microswitch 25 each time a box has been moved by the assoicated drive member 5 towards the discharge end of the apparatus.

Through appropriate electric circuit connections (not shown) the microswitches 25 and 26 control the opera- 4 be moved into engagement with the pawl wheel sega ment 19 whereby the pressure member 11 is locked against further upward movement. The electromagnet 23 remains energized until the microswitch 25 is actuated by the relevant trip dog 44 whereby the electromagnet 33 is deenergized and the pawl 20 is retracted by the spring 22, thus unlocking the pressure member 11. The type of circuitry required for controlling the operation of the electromagnet 23 by means of the two microswitches 25 and 26 in the above described manner is as such well known in the art and has therefore not been shown and described in detail.

The apparatus comprises two adhesive tape applicators, 26 and 26' mounted opposite one another on the pressure member 11 and the frame 1, respectively, in the center of the conveyor track. These applicators may be of any known type but it has been found that the adhesive tape applicator manufactured by the firm of Bandfix A.G. of Zurich, Switzerland, and marketed under the trade name Tesa model 6065 is especially suitable for use in the present apparatus. The applicators 26 and 26, as shown in the drawing representing this known device, need therefore not be described in detail. It may suffice to indicate that they each comprise two pressure rollers 27 and 28, respectively, projecting into the path of movement of the boxes through the apparatus, the adhesive tape 47 being fed to the roller 27 from a supply roll 29. The rollers 27 and 28 are mounted on spring-loaded swinging arms and may be pressed inwardly against the action of their associated springs. When an advancing box engages with its front side the roller 27 of, for instance, the upper applicator 26, the cut-off end of the tape 47 lying against this roller is pressed against this box front side and sticks thereto. The advancing box then swings the roller 27 upwards to pass underneath thereof, whereby this roller thus: presses the adhesive tape against the upper side of the box. The applicator is provided with a knife (not shown) which is moved to out the tape 47 as soon as the rear side of the box has passed the roller 27. When in the course of the continuing fob-ward movement of the box, the roller 28, which has first been pressed upwards by the front side of the box, swings downwards again behind the rear side of the box, this roller 28 presses the loose rear end of the cutoff length of tape against the box rear side. The applicator 26 applies, at the same time and in a similar way as above described, a length of tape against the bottom side of the box.

A chain 30- is connected with one end at 45 to a connecting rod 46 between the links 16. In the manner as shown in FIGS. 2 and 3, this chain 30 first runs backward to a horizontally mounted pulley 3-1, then around this pulley and sideways to a vertically mounted pulley 32, and passing around the latter extends downwards to a counterweight 33 suspended at its lower end. The pulleys 31 and 32 may be mounted in any suitable manner on supporting members secured to the frame 1 (not shown). The counterweight thus exerts, through the links 16 and the angle-cranked levers 15, an upwardly directed force on the pressure member 11. The counterweight 33 is so selected that the weight of the pressure member 11 and applicator 26 is partly compensated to such an extent that a small upward pressure on the slides 12 suffices for raising the pressure member from its lower rest position. In this rest position the slides 12 are situated a short distance above the supporting plane of the roller tracks 2.

The functioning of the above described box closing and sealing apparatus will now be explained. A cardboard box or carton 34 (FIG. 2) is placed by hand on the entry side of the roller tracks 2 or is fed thereto by means of a suitable conveyor device (not shown). The box 34 is of the conventional type having closure flaps 35 at its top side and also at its bottom side which flaps in their closed position form a longitudinal joint extending midway of the upper face and bottom, respectively, of the box. In order to close and seal the box, adhesive tape must be applied lengthwise on these joints. As shown, the upper flaps 35 of the box 34 are initially slightly raised and the box is fed to the entry side of the roller tracks in a position in which the top and bottom flaps extend at least approximately longituidnally of these tracks. The box 34 so placed on the roller tracks 2 is engaged at its rear side by a pair of drive members 5 of the two driven conveyor chains 3 which drive members advance the box into the space between the entry ends 6 and 7' of the lateral guide rails 6 and 7 and below the upwardly inclined entry ends 12' of the slides 12. The advancing box presses the spring-mounted lateral guide rails outwardly away from each other while at the same time the lower guide rails 6, through the action of their above described coupling arrangement shift the box laterally to a center position on the conveyor track. The lower guide rails 6 engage the box sides close to the bottom thereof and the upper guide rails 7 engage the box sides close to the top thereof, both exerting a sufiicient inward pressure on the box sides to make the gap of the longitudinal joints between the top and bottom closure flaps as small as possible.

The box 34 when entering between the entry ends 6' and 7 of the lateral guide rails is moved with its raised upper flaps 35 against the inclined entry ends 12 of the slides 12 whereby these flaps are gradually closed until the upper front edge of the box directly engages these entry ends 12'. On further movement of the box this upper edge thereof slides along the inclined entry ends 12' and thereby gradually raises the pressure member 11, which requires only very little upward pressure since, as described, the weight of the member 11 is for the greater part relieved by the counterweight 33. There is thus no danger that the box is tilted forwardly or damaged by its engagement with the entry slide portions 12'. Furthermore, the upward movement of the device 11 is accompanied by a small forward swinging movement thereof which further facilitates the entry of the box beneath the slides 12.

When the box has reached the position indicated by 34' in FIG. 2, its upper front edge actuates the switch arm 24 of the microswitch 24 whereby the electromagnet 23 is excited and the pawl 20 is moved to engage the pawl wheel segment 19, thus locking the pressure member 11 against further upward movement. As shown, the box actuates the switch 24 just before its front side has reached the bend of the inclined entry end portions 12' of the slides 12, the pressure member 11 thus being locked just before the box has raised the slides 12 to the level of the height of the box. These slides thus slightly compress the box on its further passage beneath the pressure member 11 and thereby provide the required closing pressure on the upper flaps 35. By proper adjustment of the microswitch 24 lengthwise of the entry end portion 12' to which it is attached the value of this closing pressure can be regulated and adapted to the stiffness of the box material and to the nature of the articles packed therein.

The box, thus enclosed between the lateral guide rails 6 and 7, and between the roller tracks 2 and the slides 12, on its further movement through the apparatus passes the adhesive tape applicators 26 and 26 which in the manner as above described apply the required, length of sealing tape 47 on the joints of the top and bottom closure flaps of the box. Because the pressure member 11 is locked against upward movement, the applicator rollers 27 and 28 can stick-on these adhesive tapes with the required pressure. The slides 12 are arranged closely adjacent the upper applicator 26 on both sides thereof whereby these slides exert a downward pressure on the top flaps 35 as close as possible to the longitudinal joint therebetween. If desired, two further fixed slides may be arranged in a similar way in the plane of the roller tracks 2 on both sides of the lower applicator 26 for exerting a closing pressure on the bottom closure flaps of the box (not shown).

After the lengths of adhesive tape have been fully applied and the rear side of the box has passed the applica tors 26 and 26', one of the trip dogs 44 actuates the switch arm 25' of the microswitch 25 whereby the electromagnet 23 is deenergized and the pawl 20 is disengaged from the pawl wheel segment 19. As soon as the rear side of the box is completely disengaged from the slides 12 and from the lateral guide rails 6 and 7, the pressure member 11 returns to its lowermost rest position and the guide rails likewise return to their innermost rest position under the action of their associated springs whereupon the apparatus is ready to receive the next box to be closed.

By lengthwise adjustment of the microswitch 25, it is possible to adapt the apparatus to the general length of the boxes to be handled in such a way that the pressure member 11 is unlocked as soon as possible after the rear side of the boxes have passed the applicators 26 and 26'. Such an adjustment of the microswitch 25 may, for instance, be required in case boxes of relatively short length are to be handled and the conveyor chains 3 are provided with three or more sets of drive members and a corresponding number of associated trip dogs 44 so as to increase the output of the apparatus.

If desired, the adhesive tape applicators 26 and 26 may be replaced by similar devices for applying gummed 8 tape which is not self-sticking but has to be moistened before being applied.

While the invention has been shown and described with reference to a preferred embodiment thereof, various modifications of this embodiment are possible within the scope of the following claims.

I claim:

1. Apparatus for closing and sealing cardboard boxes and similar packages by the application of adhesive tape on at least the upper side of the boxes, said apparatus comprising a frame, a substantially horizontal conveyor track carried by said frame, conveyor means for advancing said boxes one after another on said conveyor track, lateral parallel guide means for said boxes extendingparallel to said conveyor track along both sides thereof, an elongated pressure member extending lengthwise of and above said conveyor track and mounted for reciprocating movement toward and away from said 'track, adjusting means for adjusting the vertical position of said pressure member with respect to said conveyor track in accordance with the height dimension of a box advancing on said track toward said pressure member, an adhesive tape applicator device carried by said pressure member and adapted to apply a length of adhesive tape on a box moving underneath said pressure member, a locking device for said pressure member adapted to lock said member in any vertical position within its range of vertical displacement above said conveyor track, first control means for said locking device responsive to the passage of a box on said conveyor track and arranged for actuating said locking device when said pressure member has been raised by said adjusting means to the desired level for said box, and second control means for said locking device and arranged to release said latter device when said box has moved beyond said adhesive tape applicator device by said conveyor means.

2. The apparatus of claim 1 in which said pressure member is mounted for vertical movement by suspension means causing said pressure member to have a tendency to occupy a predetermined lowermost position above said conveyor track under the influence of a downwardly directed force, said pressure member having further guide means adapted to be engaged by an advancing box whereby said box may raise said pressure member against the action of said force to a height allowing said box to pass below said member.

3. The apparatus according to claim 2 in which said supporting means is coupled with means exerting a substantially constant force on said pressure member in opposition to the force of gravity acting on said pressure member and smaller than said latter force whereby said pressure member can be raised from its said lowermost position by a small, substantially constant upward pressure.

4. The apparatus of claim 3 in which said force exerting means comprises a counterweight.

5. The apparatus of claim 3 in which said suspension means comprises a number of pivotally mounted parallel angle-cranked levers coupled with one another for simultaneous pivoting movement, said levers having down wardly inclined lower arms suspending said pressure member and having upwardly extending upper arms coupled to said force exerting means.

6. The apparatus of claim 5 in which said locking device comprises a toothed pawl wheel segment coupled to one of said angle-cranked levers so as to rotate therewith, a moveable mounted pawl member cooperating with said toothed pawl wheel segment, and actuating means for said pawl member for moving the latter into and out of arrangement, respectively, with said toothed pawl wheel segment, said actuating means being under the control of said first and second control means.

7. The apparatus of claim 2 in which said first control means is so arranged lengthwise of said conveyor track as to respond to the passage of a box advancing along said track when said box has raised pressure member up to a level just below the height of the box.

8. The apparatus according to claim 1 in which said locking device comprises an electromagnet having an armature, a pawl member cooperating with said armature for actuation thereby, and a toothed member secured to said pressure member and cooperating with said pawl member, said first and second control means controlling the excitation of said electromagnet whereby on the actuation of said first control means said electromagnet causes said pawl member to engage said toothed member and whereby on the actuation of said second control means said electromagnet causes said pawl member to release said toothed member.

9. The apparatus according to claim 8 in which said first control means comprises a first microswitch having a switch arm projecting into the path of movement of the boxes through the apparatus.

10. The apparatus of claim 9 in which said pressure member comprises upwardly and rearwardly inclined entry guide members at its rear end facing the direction of advance of said boxes and adapted to be engaged by an advancing box allowing said box to raise said pressure member, said first microswitch being mounted on one of said entry guide members closely adjacent the lower forward end thereof whereby said first microswitch is actuated by an advancing box engaging said entry guide members just before said box has been able to raise said pressure member completely to its own height.

11. The apparatus of claim 10 in which said first microswitch is adjustable lengthwise of said entry guide member to which it is attached.

12. The apparatus of claim 8 in which said second control means comprises a second microswitch having a switch arm, and at least one trip dog secured to said conveyor means, said second microswitch switch arm projecting into the path of said trip dog to be actuated thereby.

13. The apparatus of claim 1 in which said lateral guide rail means comprise a pair of lower guide rails carried by said frame and arranged opposite one another at a small distance above said conveyor track, a pair of upper guide rails carried by said pressure member and arranged opposite one another at a small distance below said latter member, the guide rails of each of said pairs of guide rails having outwardly and rearwardly diverging entry portions for said boxes at their ends facing the direction of advance of said boxes, each pair of guide rails being mounted for lateral movement towards and away from each other, spring means for said lateral guide rails tending to move said rails inwardly, and a coupling mechanism coupling the lateral guide rails of at least one of said pairs of guide rails and forcing the two guide rails of said pair to move simultaneously in opposite lateral directions.

14. The apparatus of claim 1 in which said lateral guide rail means comprise at least one pair of guide rails arranged opposite one another on both sides of said conveyor track and having outwardly diverging entry portions for said boxes advancing on said conveyor track towards said guide rails, mounting means for each of said guide rails including two parallel horizontal supporting rods at their one ends articulated to the guide rail and at their opposite ends mounted for pivotal movement above vertical axes, and two toothed wheels meshing with one another, one of said wheels being coupled to one of said supporting rods of the one guide rail and the other of said toothed wheels being coupled to one of said supporting rods of the other guide rail whereby a lateral displacement of one of said guide rails is accompanied by an equal lateral displacement in the opposite direction of the other of said guide rails.

15. The apparatus according to claim 1 further comprising a second adhesive tape applicator device mounted in said frame opposite of said first mentioned adhesive tape applicator device.

References Cited UNITED STATES PATENTS 2,564,901 8/1951 Hess 156-351 2,597,922 5/1952 Conti l56-362 2,776,068 1/1957 Johnson 156-351 3,212,950 10/1965 Philippi 156351 SAMUEL FEINBERG, Primary Examiner US. Cl. X.R. 156367, 360, 363 

